"In my area of michigan spring time bring about an avalanche of those twirling tree seeds that fall everywhere. I just put in a new lawn from seed and the tree seeds fell in the yard as well. Naturally I could not rake them out without disturbing the new seed. Now I have tiny tree saplings growing in my grass. Dozens of them. What is the best method of getting rid of them without harming my grass which is about 4 weeks old now?"

When I lived up in Michigan I just went around and pulled them out of the ground if they are small enough you may be able to do this too.

Just mow your lawn as needed and that will kill them sooner or later. As far as the spots that do not get mowed, you have to pull or poison.